Patent GB-645828-A (GB)
Title: Improvements in or relating to stabilizers for rubber and the like, and the preparation thereof
IPC: C08K5/13
Filed: 1947-01-02
Abstract: 2,4-Dialkyl-6-terpenylphenols, (see Group IV (b)) are used as stabilizers for synthetic rubbers such as the copolymers of butadiene with acrylonitrile or styrene.  The preferred terpenylphenols are 2,4-dimethyl-6-isobornylphenol, 2,4-dimethyl-6-bornylphenol, 2,4-dimethyl - 6 - menthenylphenol, and 2,4 - di - sec. - butyl-6-isobutylphenol, although the corresponding products in which the alkyl groups are methyl, ethyl, propyl, isopropyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl or amyl groups and the terpenes are phellandrene, sylvestrene, limonene, terpinene, terpinolene, camphene, a -pinene, b -pinene, carene, fenchene, bornylene, tricyclene, and cyclofenchene may be used.  The terpenylphenol is preferably added to the rubber in emulsion and the mixture then coagulated.  In examples, the preferred terpenylphenols are added to mixtures containing sulphur and (II) butadiene-acrylonitrile, stearic acid, zinc oxide, carbon black, and N-cyclohexyl benzothiazyl sulphenamide; (III) butadiene-acrylonitrile, cumarone resin, magnesia, zinc oxide, neutral clay, titanium dioxide, benzothiazyl disulphide and zinc diethyl dithiocarbamate; (XI) butadiene-styrene copolymer, ultramarine blue, magnesium oxide, accelerator, sunproof wax, titanium dioxide and zinc oxide, which are then cured.ALSO:2,4 - dialkyl - 6 - terpenylphenols, particularly for use as stabilizers of natural and synthetic rubber (see Groups IV (a) and V), are obtained by reacting a 2,4-dialkylphenol with a terpene hydrocarbon in the presence of an acidic catalyst or a halogen at a temperature of 70 to 130 DEG  C.  The acidic catalyst may be a strong acid such as sulphuric acid, phosphoric acid, benzenesulphonic acid, p-toluene-sulphonic acid, fluoboric acid, hydrofluoric acid, stannic chloride, zinc chloride, aluminium chloride, ferric chloride, boron trichloride or trifluoride, and their ether complexes.  The reaction is preferably effected in a solvent such as benzene, toluene, ethylene chloride or cyclohexane.  In examples (1) and (2) 2,4-dimethyl-6-isobornyl phenol is prepared from 2,4-dimethyl phenol and camphene; (3) and (4), the corresponding 2,4-dimethyl-6-bornyl phenol and 2,4-dimethyl-6-menthenyl phenol are prepared from a -pinene and dipentene; (5) 2,4-di-sec-butyl-6-isobutyl phenol from 2,4-di-sec-butyl phenol and camphene.  Products may also be obtained in which the alkyl groups are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl or amyl groups; and the terpenes are phellandrene, sylvestrene, limonene, terpinene, terpinolene, camphene, a -pinene, b -pinene, carene, fenchene, bornylene, tricylene, and cyclofenchene.ALSO:2,4-Dialkyl-6-terpenylphenols, which may be made according to the process described in Group IV (b), are used as stabilizers for natural rubber and synthetic rubbers such as the coplymers of butadiene with acrylonitrile or styrene.  The preferred terpenylphenols are 2,4-dimethyl - 6 - isobornylphenol, 2,4-dimethyl-6-bornylphenol, 2,4 - dimethyl - 6 - menthenylphenol, and 2,4-di-sec.-butyl-6-isobutylphenol; although the corresponding products in which the alkyl groups are methyl, ethyl, propyl, isopropyl, n-butyl, sec.-butyl, isobutyl, ter.-butyl or amyl groups, and the terpenes are phellandrene, sylvestrene, limonene, terpinene, terpinolene, camphene, a -pinene, b -pinene, carene, fenchene, bornylene, tricyclene, and cyclofenchene, may be used.  The terpenylphenol is preferably added to the rubber in an emulsion form and the mixture then coagulated.  In examples, the preferred terpenylphenols are added to mixtures containing sulphur and: (Table II) butadiene-acrylonitrile, stearic acid, zinc oxide, carbon black, and N-cyclohexyl benzothiazyl sulphenamide; (Table III) butadiene-acrylonitrile, cumarone resin, magnesia, zinc oxide, neutral clay, titanium dioxide, benzothiazyl disulphide and zinc diethyl dithiocarbamate; (Table IX) natural rubber, zinc oxide, titanium dioxide, wax, stearic acid, ultramarine, and benzothiazyl disulphide; (Table XI) butadiene-styrene copolymer, ultramarine blue, magnesium oxide accelerator,. sunproof wax, titanium dioxide and zinc oxide.